Electronic components in central processing units (CPUs) of servers or personal computers may be required to efficiently dissipate heat generated from semiconductor elements. Such electronic components thus have structures provided with heat spreaders made of materials having high thermal conductivity such as copper, which are disposed immediately above the semiconductor elements.
The heat sources and the heat spreaders have microscopic roughness, and hence have insufficient contact areas when brought into direct contact with each other. This may result in high thermal resistance in the contact interface, disabling the electronic components to efficiently dissipate heat. To reduce the contact thermal resistance, the heat sources and the heat spreaders may be connected via thermal interface materials (TIM).
The thermal interface materials may need to have high thermal conductivity and contact properties with respect to wider microscopic roughened surfaces of the heat sources and the heat spreaders.
Examples of the related art thermal interface materials include thermal grease, phase change materials (PCMB), and indium. Major characteristics of the above example thermal interface materials may be capability of securing wider contact areas with respect to the microscopic roughened surfaces because these materials have flowability at temperatures lower than the heat resistant temperatures of the electronic apparatuses.
However, the thermal grease or phase change materials have a relatively low thermal conductivity range of 1 to 5 W/m·K. Indium is a rare metal, and the price of indium has significantly risen owing to a significant increase in the demand of indium-tin oxide related materials, which leads to much expectation of more inexpensive alternative materials.
With this respect, linear structures of carbon represented by carbon nanotubes have attracted much attention. Carbon nanotubes have a significantly high thermal conductivity range (1500 to 3000 W/m·K) as well as having high flexibility and high thermal resistance. Carbon nanotubes may thus serve as prospective heat dissipation materials.
The related art technologies propose heat dissipation structures fabricated by dispersing carbon nanotubes in resin, and heat dissipation structures fabricated by embedding a bundle of carbon nanotubes growing on the substrate with resin.